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Milk mid-infrared spectra based biomarkers contributing to genetic improvement for udder health, fertility and longevity

Publikation: Bidrag til bog/antologi/rapport/proceedingKonferenceabstrakt i proceedingsForskningpeer review

Recent research showed the usefulness of using estimated breeding values (EBV)
for mid-infrared (MIR) based biomarkers in genetic improvement. Similarly, research has also shown that genetic variation is contained in the absorbance traits along the MIR band of wavelengths. Targeted extraction of the useful genetic variance can be achieved by the combination of EBV. Direct estimation of EBV for absorbance traits was demonstrated. Our first objective was to show that the reduction of the rank of the (co)variance structure among spectral traits is possible by imposing linear functions, even if these functions represent lower accuracy MIR biomarkers. MIR based biomarkers traits were derived from ongoing research in the FP7 GplusE project. In this study, the pathway from MIR spectra to the use in genetic improvement will be described. First, blood reference phenotypic data was collected on Holstein cows, at early lactation for IGF-1, glucose, urea, cholesterol, fructosamine, beta-hydroxybutyric (BHB) acid and non-esterified fatty acids (NEFA). These traits were calibrated against corresponding MIR spectral data. Calibration Rcv 2 ranged from 0.21 to 0.51, very low from a chemometrical point of view, but potentially sufficient to extract useful spectral variation. This was validated, using EBV that were based on these MIR predictions for 144,623 records (closest to days in milk 25), from 73,378
cows, in the Walloon region of Belgium. Single-trait, but multi-lactation (1, 2, 3+)
models yielded h2 estimates ranging from 0.07 to 0.27. At least 20 daughters with novel traits and official EBV for udder health, fertility and longevity, with minimum reliabilities of 70% were required; a total of 124 bulls met this criteria. Standard selection index theory would usually rely on prediction error variance minimisation and estimated population (co)variances. Alternatively in this study, Partial Least Squares were applied to EBV for the milk MIR based biomarkers to develop novel genetic predictors for udder health, fertility and longevity, by extracting genetic variation along the wave band after rank reduction. Using all bulls, correlations between best predictors and EBV for udder health, fertility and longevity were at least 0.63, 0.67 and 0.62. Using selection index theory and based on significant increases of prediction abilities of longevity (0.76 compared to 0.68 from udder health or fertility alone) using milk MIR based blood biomarkers, their potential contribution to genetic improvement of udder health, fertility and longevity will be demonstrated.
OriginalsprogEngelsk
TitelProceedings of the ICAR Conference
RedaktørerJ. Bryant, M. Burke, R. Cook, B. Harris, C. Mosconi, B. Wickham
Antal sider7
Vol/bind23
Udgivelsesår2018
Sider221-227
ISBN (trykt)92-95014-19-7
StatusUdgivet - 2018
BegivenhedICAR Conference - Auckland, New Zealand
Varighed: 10 feb. 201811 feb. 2018

Konference

KonferenceICAR Conference
LandNew Zealand
ByAuckland
Periode10/02/201811/02/2018
SerietitelICAR Technical Series
ISSN1563-2504

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